Mixing and kneading device

ABSTRACT

A mixing and kneading device for both dry and moist products, featuring a housing with one or more agitator arms which are mounted rotatably in said housing by means of shafts provided on each side of the arms, said housing being closed off with &#39;&#39;&#39;&#39;pressure resistant&#39;&#39;&#39;&#39; seals at the points of exit of said agitator shafts. The agitator arms and shafts are designed as separate parts which are divided along planes perpendicular to the axes of rotation, and are detachably interconnected by conventional clamping elements, including respective pins coaxial to said shafts.

United States Patent Henschel 1 Mar. 21, 1972 [54] MIXING AND KNEADING DEVICE 2,852,740 9/1958 Posey et a1 ..259/l09 X Inventor: Werner Henschel, Muttenz Switzerland 3,284,056 1 1/1966 McConnaughay ..259ll0 [73] Assignee: Buss A.G., Basel, Switzerland Primary Examiner-Marvin A. Champion Assistant Examiner-Lawrence J. Staab [22] Flled' June 1969 AttorneyTab T. Thein [21] Appl. No.: 830,050

[57] ABSTRACT [52] US. Cl ..259/104, 74/598 A ixi g and kneading device for both dry and moist [51] h-lt. Cl. 7/00 roduct featuring a housing with .one or more agitator arm [58] Field of Search ..259/6, 104,9, 10,25,26, which are mounted rotatably i i housing by means f 259/21, 109, 110, DIG. 16; 287/53; 74/59 shafts provided on each side of the arms, said housing being closed off with pressure resistant" seals at the points of exit [56] References cued of said agitator shafts. The agitator arms and shafts are UNITED STATES PATENTS designed as separate parts which are divided along planes perpendicular to the axes of rotation, and are detachably inter 188,138 3/1877 Houston ..74/598 Connected by conventional clamping elements, including 225 3/1880 Young respective pins coaxial to said shafts. 722,112 3/1903 Koelner.. 870,220 1 1/1907 Brooks ..287/53 X 3 Claims, 1 Drawing Figure A 5. l l /4 4 i Patented March 21, 1972 6m MN r N a v2 m a MIXING AND KNEADING DEVICE For the mixing and kneading of both dry and moist products, use is made of so-called trough mixers and kneaders fitted with one or two agitator arms mounted in a housing.

Since this process entails working with high pressures, with a vacuum or with highly volatile substances such as solvent vapors, it is necessary for the interior of the housing to be well sealed off from the exterior. This poses problems, in particular at the exit points of the agitator arm shafts, where the seals, which generally take the form of stuffing boxes, must provide a reliable closure while not unduly complicating the dismounting of the agitator arms or their shafts.

Dismounting these elements is always necessary when changing over from one product to another. At this time, the agitator arms and the kneading trough itself must be painstakingly cleaned. In addition, dismantling the agitator arms is unavoidable whenever an expendable sheet lining is to be exchanged which lines the kneading trough.

A dismantling operation of this kind becomes particularly difficult on dual-trough kneaders with two agitator arms when they are fitted with so-called Z-arms. Should, in addition, these be required to work on products which are in a heavily viscous condition, it will e necessary, because of the great stresses involved, to mount the agitator arm shafts on both sides on force-locking bearings and possibly to drive them from both sides as well. In such cases, dismantling these shafts is not only rendered complicated and time-consuming by the stuffing boxes but is further impeded, with disadvantageous effects, by the weight of the driving components and the bearings.

Agitator arms are generally designed to be angled towards the lead-in point on the kneading trough side so as to execute their kneading motions centrally about the kneading arm shafts and at the same time to keep the lead-in points always free from material deposits. As a result, the shape of the agitator arms and the kneading process itself give rise to relatively heavy stresses at the lead-in points and at the bearings.

It is therefore considered to be an advantage to reinforce these points on the agitator arm shafts without further increasing the diameter of the stuffing boxes and bearings by making the design more massive.

The object of the present invention isto provide a mixing and kneading device, the agitator arm shaft of which can be executed in strengthened form without increasing its crosssection, the dismantling of the agitator arms remaining possible in a very short time and without great expenditure of resources.

The proposed mixing and kneading device features a housing with at least one agitator arm which is mounted rotatably in the housing by means of a shaft on each side, the housing being closed off with a pressure-resistant seal at the points of exit of the agitator shafts. The device is characterized in that the agitator arm or arms and the respective agitator shafts are designed as separate parts, divided along planes perpendicular to the axes of rotation of the agitator shafts to facilitate dismounting of the arms from the shafts; these elements are connected non-integrally by a pin with a clamping element coaxial to each shaft.

The sole figure of the accompanying drawing shows schematically an exemplary embodiment of the mixing and kneading device according to the invention.

The mixing and kneading device incorporates a housing 1 in which two agitator shafts 2a and 2b are mounted. The central portion of the housing 1 is sealed off from the exterior by means of stuffing boxes 4, 5, 6 and 7 or of seals such as are described in Swiss Pat. No. 440,876 issued July 31, 1967 to Buss A. G., Basel.

The interior of the housing 1, constituting a so-called kneading trough, is lined with an expendable sheet 21 which may for example be fitted detachably to the inside of the housing by means of bolts 22. This expendable sheet 21 serves to protect the interior wall of the housing 1, which would otherwise be subject to very heavy wear, especially when heavily viscous products are processed. It is therefore of very special interest that this expendable sheet should be easily interchangeable.

The Z-shaped shafts 2a and 2b bear agitator arms 3a and 3b, movable within the central housing portion, and are connected with one another for simultaneous and interrelated movement by means of interengaging gears 8, 9. Bearings 10, 1 l, 12, 13, l4, 15, 16 and 17 are provided for the guidance of the agitator shafts 2a, 2b as well as the arms 3a, 3b.

For a detachable connection between the agitator arms 3a, 3b and the agitator arm shafts 2a, 2b, pins 18 are provided which are fixed to the agitator shafts 2a, 2b by means of bolts 19 (shown, for the sake of clarity, only for the sectioned elements 2a, 2b in the lower half of the drawing). The agitator arm shafts 2a, 2b are provided with coaxial bores to take up these pins 18 and bolts 19. Corresponding bores are provided in the agitator arms 3a, 3b and the elements in question (arms and shafts) are joined so as to be locked for simultaneous rotation, by a bolt 20 which is covered by a plate 23 toward the central housing portion or kneading troughv As shown in the drawing, plates 23 are countersunk in the inner surfaces of arms 3a, 3b. These plates (and the described related elements) are not shown for the arm 3b which. is not sectioned, in the upper half of the drawing).

When the plates 23 and then the bolts 19 are removed, the pins 18 can be extracted and the agitator arms 30, 3b can be freely dismounted. As a result, both the arms and the kneading trough itself can be cleaned very easily, thus materially reduc ing the idling time of the machine when different products are to be processed consecutively. Exchanging the expendable sheet 21, as periodically necessary, is also considerably facilitated.

Designing the joint in this manner results in the stresses being transferred to the mixing shaft radially from the interior, and the lines of force which are asymmetrically composed of pressure and flexion moments are interrupted.

The angled arrangement of the agitator arms 30, 3b makes it possible for the clamping pins 18 to be inserted centrally at an easily accessible point on the agitator arm shafts 2a, 2b, with the result that when necessary they can be withdrawn rapidly and simply.

At the same time, the selection of a suitable shape can ensure that the point at which the pinned joint is made is stressed only relatively lightly during the heavy kneading operation, with the result that a thin steel plate is sufficient as a cover for the housing.

What I claim is:

l. A mixing and kneading device, comprising a housing, at least one agitator arm rotatably mounted in said housing by means of shafts extending to both sides, a pressure-resistant seal for closing said housing at the points of exit of said shafts, said at least one agitator arm and said shafts constituting separate parts divided along planes perpendicular to the respective axes of rotation, and clamping means including pins coaxial to said shafts, for detachable connection to said arms, wherein said shafts have coaxial bores for said pins, said clamping means includes coaxial bolts for securing said pins to the respective shafts, and said clamping means further includes eccentric bolts for preventing untoward relative rotational movement between said shafts and said at least one agitator arm, and wherein said at least one agitator arm has an inner recess facing the inside of said housing, through which said coaxial and said eccentric bolts are accessible, and further comprising a removable plate covering said recess and protecting the same and said bolts from the material treated in the device. 1

2. The mixing and kneading device as defined in claim 1, further comprising means for dismounting said at least one agitator arm and said shafts from said housing, and a detachable, expendable lining in said housing for protecting its inner walls.

3. The mixing and kneading device as defined in claim 1, further comprising means for driving said at least one agitator arm for predetermined interrelated movement by the intermediary of the free ends of said shafts, which protrude from said housing. 

1. A mixing and kneading device, comprising a housing, at least one agitator arm rotatably mounted in said housing by means of shafts extending to both sides, a pressure-resistant seal for closing said housing at the points of exit of said shafts, said at least one agitator arm and said shafts constituting separate parts divided along planes perpendicular to the respective axes of rotation, and clamping means including pins coaxial to said shafts, for detachable connection to said arms, wherein said shafts have coaxial bores for said pins, said clamping means includes coaxial bolts for securing said pins to the respective shafts, and said clamping means further includes eccentric bolts for preventing untoward relative rotational movement between said shafts and said at least one agitator arm, and wherein said at least one agitator arm has an inner recess facing the inside of said housing, through which said coaxial and said eccentric bolts are accessible, and further comprising a removable plate covering said recess and protecting the same and said bolts from the material treated in the device.
 2. The mixing and kneading device as defined in claim 1, further comprising means for dismounting said at least one agitator arm and said shafts from said housing, and a detachable, expendable lining in said housing for protecting its inner walls.
 3. The mixing and kneading device as defined in claim 1, further comprising means for driving said at least one agitator arm for predetermined interrelated movement by the intermediary of the free ends of said shafts, which protrude from said housing. 